Method and composition for amine borane reduction of copper oxide to metallic copper

Abstract

An improvement in a method of bonding copper and a resin together wherein a copper oxide layer is formed on the surface of copper by the oxidation of metallic copper, the copper oxide layer is reduced to metallic copper with an aqueous reducing solution containing at least one amine borane represented by the general formula: BH,NHRR′ (wherein R and R′ are each a member selected from the group consisting of H, CH,, and CH,CH,), and the metallic copper is bonded to a resin. According to the improvement, a reducing stabilizer is added to the reducing solution in an amount sufficient to decrease consumption of the amine borane during reduction to a level less than that consumed in the absence of the reducing stabilizer during the course of the copper oxide reduction process, wherein the stabilized reduction process is initiated in a reasonable time and the metallic copper layer resulting from the stabilized reduction process is resistant to acid attack. Examples of such reducing stabilizers include thio-containing (—C(═S)NH,) compounds, triazole-containing (C,H,N,) compounds, isoxazole-containing (—C,HNO) compounds, thiazole-containing (—NCS—) compounds, imidazole-containing (—NCN—) compounds, and sulfone-containing (—SO,H) compounds.